Printed circuit boards utilized in certain applications such as those printed circuit boards utilized in telecommunication public facilities must demonstrate the ability of conductors exposed on the surface of the printed circuit board to withstand a high-voltage surge without causing safety compromises to the end user. Regulatory compliance tests have been set up to test for such conditions. One such regulatory test is defined by the TIA968A Leakage Current Limitations test as outlined in section 4.3 of the standard. The latter test specifically requires that exposed printed circuit board conductors must not cause their dielectric insulation to break down under the response to a 1500 Vrms low-frequency sine wave of a 60 seconds duration. If the dielectric breakdown occurs between the exposed printed circuit conductors and the leakage current exceeds 10 ma, the printed circuit board fails this particular test and must be redesigned so that the exposed conductors can be in compliance with this test.
Within the prior art, the redesign of the printed circuit board has been accomplished either by simply increasing the distance between the edges of the two exposed conductors such that the dielectric breakdown is avoided between the conductors. A second approach has been to use conformal coatings between the two conductors. Although both of these prior art approaches are effective, it is very costly to have to either redesign for a larger distance between the conductors or to use conformal coatings.